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Browsing by Author "Joshi, S"

Browsing by Author "Joshi, S"

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  • HD 12098 a new far-northern roAp star 
    Girish, V; Joshi, S; Seetha, S; Ashoka, B. N; Martinez, P; Chaubey, U. S; Gupta, S. K; Kurtz, D. W; Sagar, R (Astronomical Society of India, 2001)
    The rapidly oscillating Ap (roAp) stars are cool, magnetic, chemically peculiar stars which pulsate in non-radial p-modes in the period range 4-16 min and have Johnson B amplitudes less than 8 mmag. "The NainiTal-Cape ...
  • The hot γ Doradus and Maia stars 
    Balona, L. A; Engelbrecht, C. A; Joshi, Y. C; Joshi, S; Sharma, K; Semenko, E; Pandey, G; Chakradhari, N. K; Mkrtichian, D; Hema, B. P; Nemec, J. M (Oxford University Press on behalf of the Royal Astronomical Society, 2016-09)
    The hot γ Doradus stars have multiple low frequencies characteristic of γ Dor or SPB variables, but are located between the red edge of the SPB and the blue edge of the γ Dor instability strips where all low-frequency ...
  • Intra-night optical variability of core dominated radio quasars: the role of optical polarization 
    Goyal, A; Gopal-Krishna; Wiita, P. J; Anupama, G. C; Sahu, D. K; Sagar, R; Joshi, S (EDP Sciences, 2012-08)
    Context. Rapid variations in optical flux are seen in many quasars and all blazars. The amount of variability in different classes of active galactic nuclei has been studied extensively but many questions remain unanswered. ...
  • Naini Tal-Cape survey for pulsating chemically peculiar stars - A status report 
    Seetha, S; Chaubey, U. S; Girish, V; Joshi, S; Ashoka, B. N; Gupta, S. K; Kurtz, D. W; Martinez, P; Sagar, R (Astronomical Society of India, 2001)
    The "Naini Tal-Cape survey for rapidly oscillating Ap stars", to search the northern hemi-sphere sky for pulsating stars was initiated in 1997. This is a collaboration between India and South Africa. So far about 70 stars ...
  • New pulsating variables discovered from the Naini Tal-Cape survey 
    Seetha, S; Ashoka, B. N; Joshi, S; Girish, V; Sagar, R; Chaubey, U. S; Gupta, S. K (Astronomical Society of India, 2002-09)
    The Naini Tal-Cape survey has been initiated to search for pulsations in chemically peculiar A and F type stars. Many of the magnetic A peculiar type stars exhibit rapid oscillations with periods ranging from 4-16 minutes. ...
  • Optical variability of radio-intermediate quasars 
    Goyal, Arti; Gopal-Krishna; Joshi, S; Sagar, R; Wiita, Paul J; Anupama, G. C; Sahu, D. K (Blackwell Publishing, 2010-02)
    We report the results of our intensive intranight optical monitoring of eight optically bright `radio-intermediate quasars' (RIQs) having flat or inverted radio spectra. The monitoring was carried out in R band on 25 nights ...
  • Probing Transit Timing Variation and Its Possible Origin with 12 New Transits of TrES-3b 
    Mannaday, V. K; Thakur, P; Jiang, I; Sahu, D. K; Joshi, Y. C; Pandey, A. K; Joshi, S; Yadav, R. K; Su, Li-Hsin; Sariya, D. P; Yeh, Li-Chin; Griv, Evgeny; Mkrtichian, D; Shlyapnikov, A; Moskvin, V; Ignatov, V; Vanko, M; Puskullu, C (IOP Publishing, 2020-07)
    We present 12 new transit light curves of the hot-Jupiter TrES-3b observed during 2012−2018 to probe the transit timing variation (TTV). By combining the midtransit times determined from these 12 transit data with ...
  • Rapid optical variability of TeV blazars 
    Gopal-Krishna; Goyal, A; Joshi, S; Karthick, C; Sagar, R; Wiita, P. J; Anupama, G. C; Sahu, D. K (Wiley-Blackwell, 2011-09)
    In this first systematic attempt to characterize the intranight optical variability (INOV) of TeV-detected blazars, we have monitored a well-defined set of nine TeV blazars on total 26 nights during 2004–10. In this R- or ...
  • Seeing and microthermal measurements near Devasthal top 
    Stalin, C. S; Sagar, R; Pant, P; Mohan, V; Kumar, B; Joshi, Y. C; Yadav, R. K. S; Joshi, S; Chandra, R; Durgapal, A. K; Uddin, W (Astronomical Society of India, 2001)
    Results of the seeing measurements carried out near Devasthal top on 43 nights during March to April 1999 are presented. Open air seeing measurements were carried out with a differential image motion monitor (DIMM) using ...
  • Site characterization for the UPSO-TIFR telescope 
    Sagar, R; Uddin, W; Pandey, A. K; Stalin, C. S; Mohan, V; Sanwal, B. B; Gupta, S. K; Yadav, R. K. S; Durgapal, A. K; Joshi, S; Kumar, B; Gupta, A. C; Joshi, Y; Srivastava, J. B; Chaubey, U. S; Singh, M; Pant, P; Gupta, K. G; Padalia, T. D (Astronomical Society of India, 2000)
    The Uttar Pradesh State Observatory, Naini Tal and Tata Institute of Fundamental Research, Mumbai plan to install jointly a 3 metre size optical telescope at Devasthal located east of Naini Tal about 50 km by road. The ...
  • Studies of chemically peculiar stars 
    Joshi, S (Astronomical Society of India, 2005-09)
    This thesis is on the framework of the "NainiTal-Cape Survey" programme for searching photometric variability in chemically peculiar stars, initiated in 1997 at the ARIES, NainiTal, India, in collaboration with the South ...
  • Survey for roAp stars in the northern sky from Naini Tal 
    Ashoka, B. N; Seetha, S; Raj, E; Chaubey, U. S; Gupta, S. K; Joshi, S; Martinez, P; Kurtz, D. W; Sagar, R; Kasturirangan, K (Astronomical Society of India, 2000)
    Of the 31 known rapidly oscillating Ap (roAp) stars, 28 are in the southern sky and majority of them were discovered at SAAO indicating that a systematic survey also is needed in the northern sky. Therefore, a project has ...
  • UPSO three channel fast photometer 
    Gupta, S. K; Sagar, R; Joshi, S; Ashoka, B. N; Babu, V. C; Seetha, S; Girish, V (Astronomical Society of India, 2001)
    The design and performance of a modular portable three channel fast photometer is described. It can be disassembled as single individual channels such that the system can also be used as a single channel photometer. The ...

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